From bbd6b53174ece541ac365b96886fceb05a32cf4a Mon Sep 17 00:00:00 2001
From: bong-water-water-bong <bong-water-water-bong@1bit.gg>
Date: Sat, 26 Sep 2026 13:04:07 -0300
Subject: [PATCH] convert: Zamba2-VL template, images as llama.cpp's media
 markers

llama-server passes a message with media to the template as a string holding
a marker, <__media_<id>__> with an id random per server, where each image
was. The template only knew the literal <__media__>, so the marker stayed in
the user text: the image landed inside the user turn instead of in front of
it, where Zyphra's template puts it. Find markers by their <__media_ prefix,
put them in front of the user turn, and keep Zyphra's list form as it was.

Checked: rendered with jinja2, the template gives Zyphra's prompt for its
list form and for string content with <__media__> or a random marker; in
llama-server (Zamba2-VL-2.7B, --chat-template-file) the image now starts at
prompt index 2 (<s>, <|vision_start|>), as in Zyphra's processor, where it
started at 4.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 conversion/zamba2vl.py | 48 ++++++++++++++++++++++++++----------------
 1 file changed, 30 insertions(+), 18 deletions(-)

diff --git a/conversion/zamba2vl.py b/conversion/zamba2vl.py
index 825f4b8510e2..bbaefc9f5f59 100644
--- a/conversion/zamba2vl.py
+++ b/conversion/zamba2vl.py
@@ -67,27 +67,39 @@ def set_vocab(self):
         special_vocab.chat_template = self._CHAT_TEMPLATE
         special_vocab.add_to_gguf(self.gguf_writer)
 
-    # Zyphra's template only takes content as a list of parts. llama.cpp passes a string, with a
-    # media marker where each image was; this one takes both, and puts the images in front of the
-    # user turn as Zyphra's does (mtmd wraps each in <|vision_start|> ... <|vision_end|>).
+    # Zyphra's template only takes content as a list of image and text parts. llama.cpp passes a
+    # message with media as a string holding a marker, <__media_<id>__> with an id random per server,
+    # where each image was; this one takes both, and puts the images (the markers) in front of the
+    # user turn, as Zyphra's does (mtmd wraps each image in <|vision_start|> ... <|vision_end|>).
     _CHAT_TEMPLATE = (
-        "{%- for message in messages -%}"
+        '{%- for message in messages -%}'
         "{%- if message['content'] is string -%}"
-        "{%- set text = message['content'] -%}"
-        "{%- set n_img = (text.split('<__media__>') | length) - 1 -%}"
-        "{%- set text = text.replace('<__media__>', '') | trim -%}"
-        "{%- else -%}"
-        "{%- set text = message['content'] | selectattr('type', 'equalto', 'text') | map(attribute='text') | join('') -%}"
-        "{%- set n_img = message['content'] | selectattr('type', 'equalto', 'image') | list | length -%}"
-        "{%- endif -%}"
+        "{%- set ns = namespace(text=message['content'], media='') -%}"
+        '{%- else -%}'
+        "{%- set ns = namespace(text=message['content'] | selectattr('type', 'equalto', 'text') | map(attribute='text') | join(''), media='') -%}"
+        "{%- for c in message['content'] | selectattr('type', 'equalto', 'image') -%}"
+        "{%- set ns.media = ns.media ~ '<|vision_start|><image><|vision_end|>\\n' -%}"
+        '{%- endfor -%}'
+        '{%- endif -%}'
+        "{%- set segs = ns.text.split('<__media_') -%}"
+        '{%- if segs | length > 1 -%}'
+        '{%- set ns.text = segs[0] -%}'
+        '{%- for seg in segs[1:] -%}'
+        "{%- set bits = seg.split('>') -%}"
+        "{%- set ns.media = ns.media ~ '<__media_' ~ bits[0] ~ '>\\n' -%}"
+        "{%- set ns.text = ns.text ~ (bits[1:] | join('>')) -%}"
+        '{%- endfor -%}'
+        '{%- set ns.text = ns.text | trim -%}'
+        '{%- endif -%}'
         "{%- if message['role'] == 'user' -%}"
-        "{%- for i in range(n_img) -%}{{ '<__media__>\\n' }}{%- endfor -%}"
-        "{{ '<s>user\\n' ~ text ~ '</s>\\n' }}"
-        "{%- else -%}"
-        "{{ '<s>' ~ message['role'] ~ '\\n' ~ text ~ '</s>' }}"
-        "{%- endif -%}"
-        "{%- endfor -%}"
-        "{%- if add_generation_prompt -%}{{ '<s>assistant\\n' }}{%- endif -%}"
+        "{{ ns.media ~ '<s>user\\n' ~ ns.text ~ '</s>\\n' }}"
+        '{%- else -%}'
+        "{{ '<s>' ~ message['role'] ~ '\\n' ~ ns.text ~ '</s>' }}"
+        '{%- endif -%}'
+        '{%- endfor -%}'
+        '{%- if add_generation_prompt -%}'
+        "{{ '<s>assistant\\n' }}"
+        '{%- endif -%}'
     )